Apparatus for manufacturing retractile cords



Aug. 28, 1951 w. 1.. AMES APPARATUS FOR MANUFACTURING RETRACTILE CORDS 6 Sheets-Sheet 1 Filed May 6, 1949 9 A m 0 WL w A V B \m\ o9 9r k8 \wt RON Aug. 28, 1951 w. 1.. AMES APPARATUS FOR MANUFACTURING RETRACTILE CORDS I Filed May 6, 1949 6 Sheets-Sheet 2 lNl/ENTOR W L. AME'S ATTORNEY Aug. 28, 1951 w. L. AMES 2,565,465

APPARATUS FOR MANUFACTURING RETRACTILE CORDS Filed May 6. 1949 6 SheetsSheet 5 INVENTOR W L. AMES ATTORNEY APPARATUS FOR MANUFACTURING RETRACTILE CORDS Filed May 6, 1949 W. L. AMES Aug. 28, 1951 6 Sheets-Sheet 4 RS ofv T N .N E R V 0, W W W A y B w. L. AMES 2,565,465

APPARATUS FOR MANUFACTURING RETRACTILE CORDS 7 Aug. 28, 1951 6 Sheets-Sheet 5 Filed May 6, 1949 INVENTOR W. L. AMES A T TORNEV Aug. 28, 1951 .l w. L. AMES 2,565,465

APPARATUS FOR MANUFACTURING RETRACTILE CORDS Filed May 6, 1949 6 Sheets-Sheet 6 FIG. /4

INVENTOR W. L. AMES ATT-ORNEY Patented Aug. 28, 1951 APPARATUS FOR MANUFACTURING RETRACTILE CORDS William L. Ames, Baltimore, Mil, assignor "to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application Mary6, 1949, Serial No. 91,749

(Cl. 1s--19-) 9 Claims.

1 This invention relates to apparatus for manufacturing retractile cords, and more particularly to apparatus for forming jacketed cordage into helically coiled, retractile cords.

In the telephone and other arts, it is frequently desirable to connect electrically-operated devices by a compact helically coiled, extensible cord the length of which may be extended by slight tension and which returns to its compact form when the tension is released.

An object of the invention is to provide new and improved apparatus for making retractile cords.

Another object of the invention is to provide new and improved apparatus for sequentially twisting and winding alength of jacketed cordage into a compact helix in such a manner that the twist introduced in the cordage tends to force the helical coils of the helix tightly against each other.

The present invention contemplates the forming of retractile cords from cordage having a vulcanized jacket. One method illustrating certain features of the invention comprises sequentially imparting a predetermined twist to a given length of such cordage, winding the previously twisted cordage into a compact helix, and subjecting the twisted, helically wound cordage to sufiicient heat to set the jacket in its twisted, helical form.

One type of apparatus embodying certain features of the invention for forming retractile cords from jacketed cordage, comprises means for imparting a predetermined twist to a given length of rubber covered cordage, means for winding the twisted length of cordage into a compact helix, and means for holding the helically wound cordage on the winding means so that the rubber jacket of the cordage may be heated to set it in its twisted, helical form.

A clear understanding of the invention will be had from the following detailed description of a specific embodiment thereof, when read in conjunction with the appended drawings, in which:

Fig. l is a top plan view of a portion of a twisting and winding apparatus embodying certain features of the invention;

Fig. 2 is a top plan view of a portion of the apparatus extending to the right of the apparatus shown in Fig. 1;

Fig. 3 is a front elevation of the portion of the apparatus shown in Fig. 1;

Fig. 4 is a front elevation of the portion of the apparatus shown in Fig. 2;

Fig. 5 is-a fragmentary, vertical sectional view taken along line 5-"5 of Fig. 1;

Fig. 6 is a vertical sectional view taken along line 66 of Fig. '2;

Fig. 7 is a vertical sectional view taken along line l1 of Fig. 2 with portions thereof broken away for reasons of clarity;

Fig. 8 is a fragmentary, vertical sectional vie taken along line 8-8 of Fig. 2;

Fig. 9 is an enlarged, fragmentary plan View showing a portion of the apparatus shown in Fig. 2;

Fig. 10 is a vertical sectional view taken along line -l0I0 of Fig. 9;

Fig. 11 shows a complete reactile cord that may be 'made by use of the apparatus and by practicing methods embodying the invention;

Fig. 12 is an enlarged, fragmentary view of a portion of the type of cordage used in forming the retractile cord shown in Fig. 11;

Fig. 13 is a vertical sectional view taken along line I3l3 of Fig. 12;

Fig. '14 illustrates an oven in which the helically wound cord may be subjected to heat treatment, and

Fig. 15 is a schematic wiring diagram of a control circuit for the motors operating the twisting and winding apparatus.

Referring now to the drawings and more particularly to Fig. 11, there is shown a complete retractile cord, indicated generally by the numeral 20, having a compact helical section i9.

The helical section I9 is formed by twisting and subsequently winding a predetermined length of jacketed cordage, indicated generally by the numeral 2|, in a compact helix and then subjecting it to suificient heat to set the cordage 2| in its twisted, helical shape. The jacketed ccrdage, as shown in Figs. 12 and 13, consists of a plurality of individually insulated conductors 2222, preferably tinsel conductors, positioned parallel to each other and enclosed in 'a paper tape 23 formed longitudinally around the parallel conductors. The paper covered core is enclosed in a tough elastic jacket 26 formed from neoprene (polychloro'prene) compound, or from a rubber or rubber-like compound which is extruded over the paper covered core and thereafter vulcanized or cured by appropriate heat treatment. Each end of the retractile cord has 'a portion of the jacket 26 stripped from the conductors 2222 and a solderless terminal 21 is secured on the end of each of the conductors 2222. A stay band 28 is formed around each end of the retractile cord 20 at the extremities of the jacket 25.

The rubber covered cordage 2| may be fabricated without enclosing the conductors 22--22 in a paper tape 23, or the paper tape may be served spirally around the conductors rather than formed longitudinally of the parallel conductors. While the best results are obtained when the conductors are laid parallel when the cordage is formed, the individual conductors 2222 may be twisted to form a composite core before the jacket 26 is extruded thereover and vulcanized. A more detailed description of the various types of cordage which may be formed into retractile cords appears in a copending application Serial No. 91,738, filed May 6, 1949, by T. E. Cox and F. P. Lyons for Retractile Cords and Methods of Making Them. 7

One type of apparatus for forming the helical portion IQ of the retractile cord 2!] (Fig.- 11), is shown in Figs. 1 to 10, inclusive, of the drawings. This apparatus comprises a twisting device indicated generally by the numeral 33 (Fig. 1), and a winding device indicated generally by. the numeral 3 l, which devices are mounted on a table indicated by the numeral 32. The twisting device 30, as shown in Figs. 2, 4 and 6, comprises a chuck 35 (Fig. 2) designed to grip an end of the .cordage 2!.

The chuck 35 is secured to a shaft 36 which is suitably journalled in a housing 3?, and has a bevelled gear 48 (Fig. 6) secured thereon, engagin another bevelled gear 4! journalled in the housing 31. A gear 52 is secured on the gear ll for rotation therewith and meshes with a pinion 43 secured on .the end of a shaft A4 provided on a motor 45 mounted on the table 32 adjacent to the housing 31. The pinion 43 also engages an idler gear 41, which is journalled in the housing 3'! and runs in a reservoir of oil indicated by the numeral 48, whereby the gear 4'5 carries a lubricating oil to the gear and pinion 42 and 43, respectively. When the motor .5 is energized, the pinion 43 drives the gear l2 in a direction which causes the bevelled gear 4! to rotate in a clockwise direction as indicated by the arrow in Fig. 6. Consequently, the shaft 33 and the chuck 35 secured thereto are driven in a clockwise direction, when viewed in Fig. 6.

The gear 42, which is driven by the pinion 43, in turn drives a gear 50 mounted on the end of a shaft 5! forming part of a counter indicated generally at 52'. counting wheels 5353 of the counter 42 so as to register the number of revolutions of the chuck 35 secured on the shaft 3'6. The counter 52 also is provided with indexing wheels 5555, which may be set to cause the operation of a sensitive switch 54, which is connected as shown in the wiring diagram (Fig. 15') for terminating the operation of the motor 45 when the chuck 35 has made a predetermined number of revolutions. The counter 52 is provided with a reset lever which, when actuated, serves to reset the counting wheels 53-53 and the indexing wheels 5555 to their normal starting position in which the digit of each counting Wheel is opposite the windoW of the counter while the indexing wheels register the number of revolutions desired by the chuck 35. When the counting wheels and indexing wheels are in their respective starting positions, the switch 54 isclosed and remains closed until the counter registers the number of revolutions determined by the initial setting of the indexing wheels 55-55. At this point, the switch 54 drops open and remains open until the counting and indexing wheels are reset to their respective starting positions by the reset lever.

The shaft is arranged to drive The winding device 3! consists of a channelshaped base Bil secured to the table 32 in a position at right angles to the rotating axis of the twisting head 35. A shaft Si is suitably journalled in a support 62 secured to the channel 61 adjacent to the chuck 35, and a plate 63 is secured at the opposite end of the channel 58. A substantial portion of the shaft Bl positioned between the supports E2 and 63 is provided with a conventional square thread indicated by the numeral 55. One end of the shaft El extends through the support 62 and has a pulley 86 secured thereon, which engages a belt 61 (Fig. l) driven by a pulley 68 provided on the shaft of a motor 10 secured'to the under side of the table 32 (Fig. 4). A plate 13 is mounted slidably in an upright position on parallel rods MM secured at their oppoiste end in the supports and 63. The plate 13 is provided with a bore 16, which is of such size that it clears the threaded portion 65 of the shaft 6 I.

The plate 173 is provided with a slot H extending from the top of the plate to the internal bore 16 and is designed to slidably receive a follower 80 (Fig. 7). The follower 80 has an arcuate end 8| formed thereon, which is provided with a plurality of teeth adapted to engage the thread of the shaft 6|. The follower 80 is arranged to be disengaged from the thread of the shaft Bl by a leve 82, which is pivotally mounted on the plate 13 by means of a pin 83. When the lever 82 is moved downwardly the end thereof connected to the follower moves upwardly and withdraws the arcuate end 8! of the follower from the thread 65.

A ball 84 is maintained in the end of a bore 85 provided in the plate 13 by a spring 88, and is so arranged that a portion of the ball extends into the slot H and engaged the rounded end of the lever 82. This arrangement of the ball 84 and the spring 86 serves to maintain the lever in the position shown on the drawing, that is, maintains the lever so that the follower is resiliently main tained in engagement with the thread 35 of the shaft 3!. When the lever 82 is actuated to disengage the arcuate end Of the follower Bil from the thread 65, the ball 84 moves inwardly in the bore 85 until the center of the end of the lever 82 passes beyond the center of the ball, whereupon the spring and ball then tend to hold the lever 82 in such a position that the end of the follower 8D is disengaged from the thread 65.

A gear 81 is suitably journalled in the plate l3 concentrically with the central axis of the shaft 6! and has an annular member 88 secured thereto. The annular member is provided with a key 90, which is rigidly secured to the annular mem her and slidably engages a keyway 9i provided in the threaded portion of the shaft 5|. When the shaft BI is rotated in the proper direction by the motor 10, it drives the gear 81 in a clockwise direction through the annular member 88. The gear 81 engages a gear 93 secured on the end of a shaft 54 by means of a pin 95, the shaft 9 bein suitably journalled in an ear 99 provided on the plate '53. The gears 81 and 83 are en-- closed in a housing 95 provided with a cover 3'1. Portions of the cover 9'! are broken away in Fig. '7 in order to illustrate the arrangement and operation of the follower 80, and the gears 8'5 and 93.

The portion of the shaft 94 (Figs. 2 and 8) extending beyond the ear 99 is provided with a slot E99 adapted to slidably receive the end of a rectantgular bar IIH secured on the end-0f a rodlike mandrel I02. A lever I03 is mounted pivot.- ally on the end of the shaft 94 between the sides of the slot I00, and is adapted to engage a recess I04 provided in the end of the plate "III. A ring I05 is slidably positioned on the end of the shaft 94 for the purpose of holding the lever I03 in engagement with the recess I04 of the plate "II. This arrangement of the lever I03 and the ring I05 provide a quick means for connecting the end of a mandrel I82 to the shaft 94 and for removing it therefrom. Lateral movement of the shaft 94 is prevented by a collar I06 pinned to the shaft 94 by a pin I'I so that it abuts the ear 99, and the gear 93 secured to the shaft on the opposite side of the ear (Fig. 8).

When the shaft 6| (Fig. 7) is driven by the motor 10, it drives the gear 97 in :a clockwise direction. In turn, the gear 81 rotates the gear '93 and the shaft 94 secured thereto in a counterclockwise direction. The shaft 94, in turn, rotates the mandrel I02 in a counterclockwise direction when viewed in Fig. '7. The support .62 secured to the channel 60 is provided with a projection Him for supporting the mandrel during rotation. When the shaft 6| is driven by the motor and the follower 80 is in engagement with the thread 65 of the shaft, the plate 73 moves away from its starting position adjacent to the support 62 at a constant rate of speed determined by the pitch of the thread 65. .As the plate is moved in this direction by the threaded portion of the shaft 01, the gears 8'! and '93 are driven by the shaft as described hereinabove to rotate the mandrel 102.

The mandrel I02, when rotated as described,

is designed to wind a length of cordage 2I previously twisted by the twisting device 30 into a compact helix Hi5, as shown in Fig. 9, to form the helical portion I9 of the retractile cord 20' (Fig. 11). In order for the mandrel to wind the cordage thereon when it is rotated, a clamp indicated generally at H9 is secured on the mandrel near the right-hand end thereof for receiving the beginning end of a length of cordage :2'I to be formed into the retractile. cord 20.

The clamp H0 comprises an annular member I II having a hub II2 formed thereon, which is provided with a set screw I I3 by means of which the clamp may be secured in a desired position on the mandrel IilZ. The annular member I II is provided with a peripheral groove H5, which is cut therein so as to be positioned eccentrically with respect to the axis of the clamp H0 and the mandrel 592. The left-hand face of the annular member IlI (Fig. 10-) is provided with a slot IItl through which the cordage passes from the under side of the mandrel to the peripheral groove H5. A ring I20 is mounted rotatably on the hub H2 of the clamp, and is provided with an arcuate projection I2I, extending across the groove I I and slidably engages the periphery of the annular member. The ring I20 is rotated in the direction indicated by the arrow in Fig. 10, to move the projection IZI over the shallow portion of the peripheral groove H5 and clamp the end of the cordage 2| tightly between the bottom of the groove and the projection IZI (Fig. The clamp is so designed that the cordage passes from the peripheral groove I I5 through the left-hand face of the annular member III substantially tangent to the under side of the mandrel I62, when viewed in Figs. 2, 9 and 10'.

A second clamp I25 is positioned on the mandrel I232 for the purpose of clamping the left end of the completed helix I00 on the mandrel I02.

The clamp 12.5 is identical in construction and operation with that described for the clamp H0 and is positioned on the mandrel so that the slot therein is adjacent to the end of the helix I09. The clamp II 0 is secured on the mandrel and remains in a fixed position thereon with respect to the right end of the mandrel. The clamp I25 is not fastened to the mandrel at the beginning of the winding operation but remains loose thereon so that the mandrel IE2 may slide therethrough as the cordage 2| is wound on the mandrel.

The twisting device 30 and the winding device 3| operate in conjunction with tensioning de vices indicated generally at I39 and I3I (Figs. 1 and 5). Since the tensionin devices I30 and I3I are identical in construction and operation, only the tensioning device I3! and its mode of operation will be described in detail.

The tensioning device I3I includes an elongated channel-shaped track I35 having inwardly extending flanges flit-I35, and a carriage in dicated generally at I45 positioned movably in the track I35 and connected to a weight I41 by a steel cable I46 (Fig. 1). The carriage I45, as shown in detail in Fig. 5, comprises a channelshaped body I60 having wheels ItI-Ifil provided thereon for free movement within the track I45. A lever I53 is pivotally mounted at the lower end thereof 011 a pin I64 secured in the side walls of the body I50, and the opposite end thereof is pivotally mounted in a bifurcated end I68 of a chuck I58 by a pin I65. The chuck I68 is designed to grip an end of the cordage 2I in a manner hereinafter to be described. The lever I53 is provided with a shoulder I13 adjacent to the lower end thereof, which engages the end of a lever Il5 secured on a pin I'IB suitably journalled in the side walls of the body I 60. The ends of the pin Il'8 extend beyond the side walls of the body I50, and levers Ids-48E? are secured thereon for movement therewith. Each of the levers I-I8il is provided with a brake shoe I8! of a suitable friction material, which is normally positioned slightly beneath the under side of the flanges HIE-I36 .of the track I35. A spring I82 is arranged to urge the right-hand end of the lever I15 (Fig. 5) downwardly, and turn the pin I75 so that the brake shoes I8II3i engage the under surface of the flanges of the track and prevent the carriage from II'lOVlllg in the track I35. When the lever I63 is pivoted about the pin I64 in a clockwise direction, the shoulder I73 raises the right-hand end of the lever I15 and thereby disengages the shoes I-8I-I8I from the flanges I30I36.

A post i85 (Fig. 5) is secured to the end of the body I60, and receives one end of a tension spring I86, the other end of which spring is connected to one end of the cable I46. The cable I lB- extends from the spring I08, and passes alternately around a group of pulleys I-I9fv mounted on a "bracket I9I and a group of pulleys I'M-92 mounted on a bracket I93 secured to the weight M1, with the other end thereof secured to the bracket I93. The weight Ml thus connected to the carriage I45 urges the carriage toward the left end of its track, when viewed in Figs. 1 and 3. The system of pulleys [90-596 and I92I 92 is provided between the weight I47 and the carriage I45 so that the weight travels a substantially shorter distance vertically than the distance the carriage I45 travels from the right-hand end to the left-hand end of its track I35. The weight I41 is positioned in a cylindrical housing I95 suitably mounted on the floor supporting the table 32, and rubber pads I95I96 are positioned at the bottom of the housing I95 to cushion the impact of the weight as it strikes the bottom of the housing.

The track I35 of the tensioning device I3I is secured to the top of the table 32 by supports I98-|98 (Fig. 4), which elevate the track so that the chuck I 68 provided on the carriage I45 is aligned horizontally with the winding axis of the mandrel I52. The carriage I45 is provided with a plate 200 designed to actuate a lever 20I of a sensitive switch 232 positioned near the righthand end of its track (Figs. 2 and 4) The switch 202 is mounted on a plate 203, which is positioned adjustably on a support 204 by means of a slot 205. The sensitive switch 232 is located near the end of the track I35 adjacent to the winding device SI for the purpose of terminating the operation of the winding motor I when the carriage I45 reaches a point near the right-hand end of the track. The track I35 is provided with a stop 208 positioned adjustably therein adjacent to the left-hand end of the track, when viewed in Figs. 1 and 3, which serves to limit the travel of the carriage I45 in that direction that may be effected by the weight NH.

The tensioning device 533 includes an elongated track 207 (Figs. 1 and 2) mounted on the table 32 as described for the track I35 and having a stop 208, and a carriage indicated generally at 209 movably positioned in the track and connected to a weight 2 I 0 by a steel cable 2 I I in the manner described for the carriage I45. The carriage 209 is provided with a chuck 2 I2 designed to grip an end of the cordage 2| and a plate 2E3 adapted to operate a sensitive switch 2 54 positioned near the end of the track 201 adjacent to the winding device 3|.

A supply of the cordage 2| is provided on a reel 2|5 (Fig. 4:), which may be mounted rotatably in a suitable manner under the table 32. The cordage 2! is withdrawn from the reel 2 I 5, and passes through a bell-shaped aperture provided in a guide member 2I6 secured to the table 32. cordage passes upwardly and around a pulley 2|! mounted on a bracket 2 I 23 secured on the housing 31 to a clamp indicated generally at 220. The clamp 220 consists of a support 22I secured on top of the housing 3? and having a catch 222 pivotally mounted thereon above a plate 223. The cordage 2| passes between the free end of the catch 222 and theplate 223, and in so doing moves the free end of the catch 222 to the left so that the catch is positioned angularly on the support 22I. This position of the catch permits free movement of the cordage between the end of the arm 222 and the plate 223 from right to left, when viewed in Fig. 4, but the weight of the catch and the angle at which it rests on the cordage prevents movement of the cordage from left to right. This arrangernent of the clamp serves to maintain an end of the cordage 2| available so that it may be clamped in the chuck I03 of the tensioning device I3I.

The chuck 35 of the twisting device 30, and the chucks I68 and 2I2 provided on the carriages I45 and 233, respectively, are identical in construction and operation. Hence, only the chuck I68 provided on the carriage I45 will be described in detail. The chuck I50 is provided with a pair of tapered jaws 224224 (Fig. 1), positioned slidably in the chuck So that the end of the cordage 2| may be positioned therebetween. The side walls of the chuck are tapered inwardly towards the I.

The

free end of the chuck, whereby movement of the jaws toward the free end of the chuck causes the adjacent faces of the jaws to move closer together and to grip the cordage positioned therebetween. The adjacent surfaces of the jaws 224-224 are knurled to prevent the cordage from slipping out of the chuck. A pin 225 is provided on one of the jaws 224 to facilitate positioning the jaws within the chuck I08 so that the end of the cordage 2| may be inserted between the jaws, and to move the jaws so the end of the cordage may be removed from the chuck, when desired.

The end of the cordage 2| is inserted into the chuck I 08 while the carriage I 45 is held at the right end of the track I35 by the pressure of the brake shoes I8I-I8I against the flanges I36- I36. The connection of the cordage in the chuck actuates the lever I15 and disengages the brake shoes I8|-|8I, from the flanges and allows the carriage to travel to the left against the stop 206. The travel of the carriage I45 to the left withdraws the cordage from the reel 2 I5, and in so doing measures the length of the cordage 2| required for a retractile cord, like the retractile cord 20 (Fig. 11). The cordage 2| is out near the clamp 220 to provide a length of cordage, and the free end of the length is inserted between the jaws of the chuck 35. The tension exerted on the length of cordage by the weight I41 causes the jaws of the chucks 35 and IE8 to grip the end of the cordage tightly between the knurled surfaces thereof.

When the chuck has been rotated in a clockwise direction (Fig. 6), the desired number of times determined by the counter 52 to twist the length of cordage between the chucks 35 and IE8, the end of the cordage gripped by the chuck 35 is removed therefrom, and is inserted in the clamp IIO secured on the mandrel I02. The mandrel is rotated as described to wind the twisted length of cordage on the mandrel in the compact right-hand helix I09. The weight I41 connected to the carriage I45, keeps the cordage in a straight line between the chucks 35 and H58 while the cordage is twisted by the chuck 35, and between the chuck I68 and the clamp H0 while the twisted cordage is wound on the mandrel I02.

In Fig. 14, there is illustrated an autoclave, indicated generally by the numeral 223, which may be of any conventional design. As shown, the autoclave includes a cylindrical housing 221 provided with wall plates 223228 having juxtaposed grooves provided therein for receiving projections 229229 provided on racks 230-230. The racks 230230 are designed to receive a plurality of mandrels I02I02, each mandrel having a compact helix I09 of the cordage 2| wound thereon and clamped in its compact helical position by the clamps H0 and I25. The housing 225 is provided with a hingedly mounted door 23I which is arranged to be clamped in its closed position by a plurality of hingedly mounted bolts 232-232 provided with suitable wing nuts 233 233.

When the door 23| is in its closed position, steam under a desired pressure is admitted into the housing 226 by means of a pipe 2313 connected to a suitable steam supply (not shown). The lengths of cordage wound on the mandrels positioned in the autoclave are subjected to heat therein sufiicient to relieve substantially all the stresses set up in the cordage resulting from winding it helically on the mandrel, but to relieve only a portion of the torsional stress set 9 up in the cordage by twisting. it inu the manner described. As a result, the heat sets the jack ets of the lengths of cordage in their twisted, helical shapes on the mandrels, whereby. each jacket retains the cordage in its-helical shape, substantially like that of. theretractil'e cord 20-: (Fig. 11) after it is-removed from. the mandrel. If desired, the autoclave 226 maybe replaced by an electrically: heated oven, or the like, of conventional design,

A typical electrical circuitior controlling thev operation of the twisting motor 45- andthe coiling motor 10' isshowninFig'. 15. A-suitable source of three-phase, A. C. potential-may be connected to terminals 235-235,. which are con-- necteddirectly tothe motor Til-in series with-a plurality of normallyoper-r contacts 23fi-2'3fipro V-ided on a relay-indicated generally-$231. Therelay' 231 is provided with arr operating coil-240 which is connected acrcssa single phase of the three-phase supply connected to the terminals 235-235 in series with thenormallyclosed contacts of the s'ensitive switches 20-2 and 244, a normally closed stop push buttorr contact 3% and a normally-open start push button contact- 2'42. The motor III' is energized 'by operation ofthe start push button 242 which energizes the relay 231 to close the c'ontacts'-236-236. The relay 231- is provided with a normal-l-y openaux' iliary contact 245'forthe purpose of bridging the start button and thereby holdingthe coilon itsenergized'state when the start button is released. When either of the normally closed contacts of the switches 2'02 and 2M are opened by the movement ofthe' carriages I45 and- 259,- respectively, the relay" 231 is deen'ergizedwhich terminates the operation of themotor-lm The twisting motor 45 receives its potential from a transformer 246 having its primary winding connected directly across-one phase of the three-phase supply connected to the terminals: 235 -2 35. The transformer 246 steps down the potential supplied to the terminals 235-235 tothat required to-operate'the motor-'45. The motor 45 is connected-across the-primary winding. of the transformer series with the contact 54 providedin the counter 52, and the normally open contacts of a two-pole safety switch 25k which normally is maintained in its-actuated position. The contact 54 is arranged to be actuated by the indexing wheels 55-55, one of which isillustrated schematically inFigr1 5. When the counting wheels 53-53 and the indexing wheels are positioned in their normal starting position with respect to each other by the resetlever 56, the switch 54 is closed, whereby the motor 45 .is energized and rotates the chuck-35 in the manner described hereinabove.- Whenthe counting wheels indicate that the chuck. has made the number of revolutions initially set on the indexing wheels 55-55, the indexing wheels have been advanced until the 0 digits thereof are positioned directly opposite the window of the coun-- ter, in which case,- the switch 54 drops open and disconnects the motor45 from the circuit thereby terminating the rotation of the chuck 35.

Operation The above-described apparatus operates in the following manner to form lengths of jacketed cordage, like thecordage 2t, into helically wound retractile cordslike that-shown Fig. 11

Let it be assumed that a reel 2I5 containin a supply of the rubber jacketed cordage H has been positioned underthe table 32 and the end thereof has been passed through the bushing 2I6 around the pulley 2H and. between the catch 222 in the counter whereupon th motor 45 is not energized.

Assuming that the carriage I45 is positioned at thexright-hand end of its track, the end of the cordage 2t is inserted between the jaws 224-224 Fig. l) of the chuck I53 provided on the carriage 45. The weight I471 attached to the carriage I45 tends to pull the carriage to the left. Since the cordage 2i is connected to the chuck I58, the weight creates sufiicient tension in the cordage to pull the lever I53 in. a. clockwise direction about the pin its and to raise the end of the lever I15 so as. to disengage the brake shoes ItlI-IBI from the track I35. The weight i i-i then draws thecarriage I45 to the left, until the carriage finally engages the stop 255 which is positioned in the track. This movement of the carriage I45 withdraws the cordage 2I from the reel 2I5 and in. so doing. measures out a length of cordage required to make aretractile cord.

When the carriage I45 reaches-the stop 2%,. the co-rdage is severed at apoint adjacent to-the clamp 228., and. the end thereof is inserted between the jaws 225-224 of the chuck 35 of the twisting device 35. The end of the cordage 2i is pushed into the chuck 35 untilthe cordage is taut between the chuck 35 and the chuck 1 58.. When the carriage E45 is in this position, the weight I4T exerts tension on the length of cordage 2I secured between the chucks 35 and I68.

After the length of cordage 2t is stretched between the chuck I68 and the chuck 35, the reset lever 55 of the counter 52 is actuated to reset the counting wheels 53-53 and theindexing wheels to their starting position, in which position the index wheels close the switch 54, which connects the motor 45 across the primary winding of the transformer 255. The motor is energized and rotates the chuck 35 in a clockwise direction as indicated by the arrow in Fig. 6 ofthe drawing. The rotation ofthe chuck di'n thisdirection', twists the length of cordage heldbetween't'he chuck 3'5 and the chuck IE8, whereby the parallel conductors 22-22 are twisted about each other in a long-lay, right-hand spiral, as shown in Fig. 9 of the drawings.

The motor 45 continues to rotatethe chuck 3'5 and to twist the cordage Z'I until the counting wheels 53-53 indicate that the chuck 35" has been rotated the number ofrevolutions initially set on the indexing wheel's 55-55. Whenthe counting wheels reach this point, the switch 54 drops open and disconnects the motor"45"irom' the transformer 245 and thereby terminates the twisting operation of the cord'age 2!.

During the twisting operation'on the length of cordage, the weight I41; connected to the'car riage I45, holds the cord'age taut'inspite o'fthe fact that the cordage is being twisted. When the twisting operation terminates,'the weight I47 con tinues to hold the cordage" taut and prevent "the twist from forming kinks in the length of cord age. Duringthe twisting operation-the twist im- 11 parted to the cordage shortens the cordage somewhat and withdraws the carriage slightly from the stop 206.

The amount of longitudinal twist needed in a given length of cordage depends upon various factors, such as the internal structure of the cord, that is, the manner in which the conductors 2222 are formed into a composite core before the jacket 26 is supplied thereover, the age of the jacket on the cordage, the diameter of the jacketed cordage and the particular vulcanizable compound from which the jacket 26 is made, the thickness of the jacket, and the diameter of the mandrel on which the length of cordage is wound. In any event, the indexing wheels of the counter 52 are set so that the motor 45 imparts the number of twists required for the particular cordage being used.

When the counter 52 terminates the twisting of the length of cordage 2|, the end thereof is removed from the chuck 35 and is positioned in the clamp III] provided on the right-hand end of a mandrel I02, which is secured to the end of the shaft 96. Let it be assumed that the lever 82 is actuated to disengage the follower 80 from the thread 65 and the plate I3 moved so as to slide the mandrel I02 to the left when viewed in Fig. 9 and position the clamp IIO adjacent to the chuck 35, while the chuck 35 was rotated to twist the cordage 2|. In positioning the end of the twisted cordage in the clamp III], care is exercised to preserve the previously imparted twist. To secure the end of the cordage in the clamp, the end is passed under the mandrel I02 and then is pressed in the slot I|6 so that a portion of the end may be formed around the arcuate groove II5 provided in the periphery of the annular member I I I. The portion of the end of the cordage positioned in the groove of the clamp is allowed to unwind so that the conductors 2222 at the end of the cordage are parallel with each other in order that the jacket 25 may be readily stripped therefrom when desired. When the end is positioned in the arcuate groove N5, the ring I2li is turned in a clockwise direction, when viewed in Fig. 10, so as to clamp the cordage tightly between the bottom of the shallow portion of the groove H5 and the projection I2I provided on the ring I20.

When the end of the cordage is secured in the clamp IIO, the push button 242 is actuated to energize the operating coil 240 of the relay 231, which in turn, closes the contacts 23B235 and connects the motor I0 directly to the supply terminals 235-235. This energizes the motor, which, in turn, drives the shaft 6| so that the thread 65 provided thereon, moves the plate I3 laterally away from its normal starting position adjacent to the chuck 35. The shaft 6| also drives the mandrel I02 and the clamp III) through the gears provided in the housing attached to the plate I3 in a clockwise direction when viewed in Fig. 10, whereby the twisted cordage 2| is wound around the mandrel I02 in the form of the helix I09. wound from the under side of the mandrel as it rotates in a clockwise direction in order to form the helix I09 as a right-hand helix. That is, when looking toward the free end of the mandrel, the cordage is wound thereon from left to right, or the cordage proceeds along the mandrel toward the clamp H0 in a direction analogous to that of a right-hand screw thread. The shaft 6| moves the mandrel I02 to the right as the cordage is wound thereon at a rate which The cordage 2| is causes the individual coils of the helix I09 to lay' against each other.-

As the mandrel winds the cordage 2| thereon to form the compact helix I09 (Fig. 9), the carriage I is moved slowly along the track I45 until the plate 200, carried thereby, actuates the lever 209 of the micro-switch 2|0, whereby the normally closed contact thereof is opened and denergizes the coil 240 of the relay 231. This causes the contacts 236-236 to open and disconnect the motor 10 from the terminals 253235. When the carriage reaches this point, the required length of the twisted cordage 2| has been Wound on the mandrel I02 to form a complete helix I09 having a predetermined length. The clamp I25, which was slidably positioned on the mandrel I20 throughout the winding operation, is moved to the right when viewed in Fig. 9, until the right-hand face thereof abuts the left-hand end coil of the helix I09 wound on the mandrel. The set screw |I3, provided in the clamp, then is turned to look the clamp in the proper position so that the end of the cordage secured in the chuck I68 may be removed therefrom and clamped in the clamp I25 in the same manner as has been described for the clamp H9. The end of the cordage 2| between the clamp I25 and the chuck I68 is also permitted to unwind so that the jacket may be readily stripped from this end of the cordage when desired.

Having clamped the helix I09 tightly on the mandrel I02, the mandrel is removed from the end of the shaft 94 by sliding the ring to the right, when viewed in Fig. 8, and then withdrawing the mandrel to the left so as to raise the pivotally mounted lever upwardly and out of engagement with the recess I04. The mandrel I02 containing the compact helix I09 (Fig. 9), having the ends thereof clamped securely in the clamps H0 and I25, is placed in a rack, like the racks 230-230 shown in Fig. 14. When a sufficient number of mandrels like the mandrel I02, having a compact helix wound thereon are accumulated to fill the rack 230, the filled racks are inserted in the autoclave 225, and are subjected to suflicient heat therein to cause the jacket 26 of the helically wound cordage 2| to set permanently so as to retain the cordage in its helical shape when the clamps are removed, whereby the length of cordage 2| now appears as the retractile cord 20 (Fig. 11).

It should be noted that the cordage 2| is wound on the mandrel I02 in the same direction as that in which the cordage was twisted. The chuck 35 5.. twists the length of cordage in a clockwise direction, when viewed in Fig. 6, and thereby twists the conductors 22-22 in a right-hand spiral, as shown in Fig. 9. The length of twisted cordage 2| is wound on the mandrel in a clockwise direction to form a right-hand helix I09, when looking at the free end of the mandrel. Because the cordage is wound on the mandrel in the same direction that it was twisted, the twist of the cordage causes the coils of the helix to draw together and remain in a compact helix after it is subjected to heat treatment and removed from the mandrel. The heat treatment of the cordage sets the cordage in its helical shape, but the twist introduced in the cordage causes the helical portion of the retractile cord to resiliently retain its compact helical form upon repeated extension and retraction of the cord 20.

The diameter of the mandrel I02 used in forming the retractile cord 20 is determined by the final diameter that is desired for the retractile cord 20. The cordage 2| must be wound on a mandrel having a diameter which will produce a helix thereon having an outside diameter somewhat smaller than the final diameter of the retractile cord, because, after the compact helix wound on the mandrel M32 i subjected to heat in the autoclave to set the cordage in its helical shape and the clamps l itl Ill are removed, the helix unwinds slightly and thereby assumes an outside diameter greater than that at which it was wound on the mandrel I02. This is due to the fact that the heat treatment does not relieve all of the stresses set up in the jacket 26 due to the coiling or" the cordage on the mandrel.

At the same time that the helix IE9 un-winds on the mandrel when the clamps are removed, the torsional stresses set up in the cordage by twisting the cordage before it was wound on the mandrel tend to draw the individual coils of the helix closely together. Therefore, as the helix IUQ unwinds, the torsional stresses set up in the cordage 2! due to the twisting thereof, cause the coils of the helix ltd to draw together, whereby the overall length of the helix I69 assumes a somewhat shorter dimension than that which it had when it was wound tightly on the mandrel. All of these factors are determined by testing and experience in order to obtain a retractile cord 25 having the desired dimensions which render it most favorable for its intended use.

The mere winding of the cordage 2| on the mandrel H32 in compact helical form and subjecting the jacket to sufficient heat to set the jacket 25 so that it will retain the cordage in its helical shape when removed from the mandrel, will not in itself produce the required retractility required for retractile cords. Even though the cordage is wound in a tight helix on the mandrel and given the heat treatment, the helix will not remain in its compact form when it is released from the mandrel. It is the introduction of the twist in the cordage in the same direction in which the cordage is wound on the mandrel that provides the eiiective retractility in the retractile cord 2s; The twisting of the cordage 25 before winding it on the mandrel, sets up torsional stresses tending to form the cordage into helical coils, which are, in a sense, uncontrolled in their formation and would assume the form of knots or kinks in the cordage if the ends were allowed to move together. During the twisting operation the weight connected to the carriage prevents the torsional stresses from forming kinks or knots in the cordage. When the twisted cordage, having the torsional stresses set up therein, is wound helically on the mandrel and is clamped in this position while the jacket is submitted to sufiicient heat to set it in its twisted, helical shape, the helically set jacket controls the torsional stresses in the cordage so that they tend to form uniform helical coils in the cordage. Since the jacket is set in a helical form by the heat treatment, the torsional stresses confined therein resiliently urge the individual coils of the helix closely together and thereby increase the retractility of the cord. When a retractile cord, like the cord 26, is manufactured in accordance with the procedures outlined above, the cord produced will retain its helical shape when repeatedly extended and retracted.

The above-outlined procedure may be followed in producing helically wound cords on mandrels by using only one tensioning device |3I including the carriage I45, the track I35 and the weight {"41 and performing the winding operation on the mandrel I02 after the twisting operation is com pleted by the chuck 35. However, there is shown on the drawing a second tensioning device I30, including a carriage 209 adapted to operate in its respective track ZIII'I and a weight 2H for the purpose of increasing the production of retractile cords. In using an apparatus provided with a pair of tensioning devices I30 and I3I, the operation would proceed as follows:

A length of the cordage 2| required to make a retractile cord is positioned between the chuck 2|2 provided on the carriage 289 and the chuck 35 and twisted a predetermined number of times in the manner described above. During the twisting operation, a mandrel I02 is inserted in the end of the shaft 94 preparatory to winding the twisted cordage thereon. The end of the twisted cordage is removed from the chuck 35 and secured in the right-hand clamp III! pro- Vided onthe mandrel 9'32 in the manner described, and the button 242 is actuated to energize the motor it and startwinding the previously twisted cordage on the mandrel m2. While the motor IQ of the winding device 3| is operating to wind the twisted cordage on the mandrel I92, another length of the cordage 2| required to make a retractile cord is positioned between the chuck I68 of the carriage I45 and the chuck 35 of the twisting device 30 and twisted a predetermined number of times by the chuck 35 as described hereinabove. Figs. 1 to 4, inclusive, illustrate this simultaneous operation of the twisting device it with the tensioning device I30 and the winding device 3| with the tensioning device I3I.

By the time the carriage 209 reaches the end of its path of travel on its track 2M and actuates its respective sensitive switch 254 to deenergize the motor I0 and terminate the winding operation of the twisted cordage on the mandrel, the second length of cordage is twisted fully. The mandrel I62, having a complete helix Ida wound thereon, is removed from the end of the shaft |94 as described and a second mandrel like the mandrel N32 is connected for rotation therewith. The end of the second length of twisted cordage 2| is removed from the chuck 35 and secured in the clamp Ill) positioned on the mandrel. The motor IE1 then is energized to rotate the mandrel which winds the length of twisted cordage suspended between the chuck I68 and the clamp III] thereon as described. While the second length of cordage is being wound on the mandrel, another length of the cordage 2| is withdrawn from the reel 2I5, and suspended between the chuck 2I2 and the chuck 35 and twisted. Thus, the twisting and winding devices 30 and 3|, respectively, are operated alternately between the carriages I45 and 209 to twist and wind the twisted cordage in a compact helix on the mandrels l-fl2|02. As a result, the number of cords that may be produced by such an apparatus is substantially increased over that which could be obtained by the use of a single tensioning device.

To illustrate the invention more clearly, let it be assumed that retractile cords, like the cord 2?] shown in Fig. 11, are to be formed from threeconductor cordage 2|, in which the individual conductors 22-22, shown in Figs. 12 and 13, are laid parallel with each other, enclosed in a paper tape, and thereafter the assembly is covered by a neoprene compound which is thereafter cured to form a tough, resilient jacket 26. The cordage 2! has an outside diameter of 0.205 inch and the mandrel on which it is wound has a diameter of 0.25 inch. A supply of the cordage 2| is provided aeeaeee on the reel 215, and the end thereof is withdrawn through the apparatus to the clamp 220 as described. lhe end of the cordage 2I is secured in the chuck I68 of the carriage M0. The stops 206 and 208 are adjusted on the tracks so that each weight, as it draws its respective carriage to the left-hand end *of its track, will withdraw approximately nine feet of the cordage 2| from the reel, that is, at least nine feet of cordage will be suspended between the chuck 35 and the chuck of the particular carriage in use for each twisting operation.

It has been found that an average of seventyfive twists should be introduced into a nine foot length of cordage of the type described to introduce suffioient torsional stresses in the twisted cordage to cause the helical coils of the retractile cord to remain against each other. Therefore, the indexing wheels of the counter 52 are set to deenergize the motor 35 each time it rotates the chuck seventy-five revolutions. rotates in a clockwise direction When viewed in Fig. 6 and twists the individual conductors 2222 of the cordage it into a long-lay right-hand spiral, as shown in Fig. 9 of the drawings. Only wound on the mandrel, in a compact helix I09, the remaining one foot being secured in the clamps i I and I25. When eight feet of the cordage has been wound on the mandrel to form the compact helix I09, the helix has a diameter of approximately 0.660 inch and a length of approximately eighteen inches.

The compact helix wound on the mandrel I02 then is placed in the autoclave 223, as described, and is heated at a temperature of about 300 F. for approximately ten minutes to set the cord in its twisted, helical shape. Upon the completion of the heat treatment received in the autoclave, the clamps He and I25 are removed from the mandrel, whereby the helix Hi9 wound thereon is released and allowed to assume its final size and shape indicated by the numeral i9 (Fig. 11) When the helix is released, it unwinds slightly with the result that the final diameter of the helix is approximately 0.750 inch while the overall length of the helix, which originally was eighteen inches between the clamps M0 and I25 on the mandrel, is reduced to approximately eleven inches.

The chuck 'eight feet of the twisted cordage 2| actually is The degree of retractility to be introduced in I any retractile cord depends on its use. In the telephone industry the resiliency of the retractile cord is designed to permit the receiver of a telephone instrument to be removed and withdrawn so that it may be used without disturbing the position of the instrument to which the other end of the retractile cord is attached. In cases where the transmitting instrument is firmly secured against movement, the retraotility of the cord may be substantially increased without impairing the usefulness of the cord.

What is claimed is:

1. An apparatus for forming cordage having a vulcanized jacket into retractile cords, which comprises a pair of spaced supports for gripping end portions of a length of the jacketed cordage required to make a retractile cord, means for tensioning the length of cordage between the spaced supports, means for rotating one of the supports relative to the other'to impart a predetermined twist to the length of cordage, means for winding the twisted length of cordage while under tension into a compact helix having a pitch extending in the same direction as the pitch of the twist imparted to the cordage, and means for holding the helix in its compact helical form on the winding means so that the cordage may be set in its twisted, helical shape.

2. An apparatus for forming cordage having a vulcanized jacket into retractile cords, which comprises means for tensioning a length of such cordage required to make a retractile cord, means for imparting a predetermined twist to the length of cordage, means for winding the twisting length of cordage into a compact helix against the action of the tensioning means, means operable by the tensioning means for terminating the rotation of the winding means when a predetermined amount of the length of cordage is wound thereon, and means for holding the helix in its compact form on the winding means so that the cordage may be set in its twisted, helical shape.

3. An apparatus for forming cordage having a vulcanized jacket into retractile cords, which comprises means for imparting a predetermined twist to a length of the jacketed cordage required to make a retractile cord, winding means positioned transversely to the length of cordage, means for clamping one end of the twisted cordage on the winding means, means for rotating the winding means in such a direction as to Wind the length of twisted cordage in a compact helix whose pitch is in such a direction that the twist previously introduced in the cordage tends to force the adjacent turns of the helix closely together, means for tensioning the length of cordage as it is twisted and as it is wound on the Winding means to form a helix of uniform diameter on the winding means, and means for moving the winding means transversely with respect to the length of cordage so that the adjacent convolutions of the helix wound thereon abut each other.

4. An apparatus for forming multi-conductor cordage having a vulcanizable jacket into retractile cords, which comprises a reel containing a supply of such cordage, slidable tensioning means attachable to one end of the cordage for withdrawing a length of the cordage from the reel required to make a retractile cord, a rotatable chuck for gripping the opposite end of the length of cordage, said tensioning means serving to hold the withdrawn cordage taut between the chuck and the tensioning means, means for rotating the chuck to impart a predetermined, longitudinal twist to the length of cordage, a mandrel positioned tranversely to the twisted cordage, means for clamping one end of the twisted cordage to the mandrel, means for rotating the mandrel in such a direction as to wind the twisted length of cordage against the action of the tensioning means into a compact helix having a pitch in the same direction as the pitch of the twist introduced into the length of the cordage, means for clamping the opposite end of the helix on the mandrel to hold it in its compact helical form so that the vulcanized jacket of the cordage may be set in its helical, twisted form.

5. An apparatus for forming multi-conductor cordage having a vulcanizable jacket into retractile cords, which comprises a rotatable chuck designed to grip one end of a length of such cordage required to form a retractile cord, a clamp slidable longitudinally with respect to said chuck and designed to grip the opposite end of the length of cordage, tensioning means for urging the slidable clamp away from the rotatable clamp to tension the length of cordage between the chuck and the slidable clamp, means for rotating the chuck so as to impart a predetermined longitudinal twist to the length of cordage, a mandrel positioned transversely to the length of cordage and having means for clamping one end thereof to the mandrel, means for simultaneously rotating and moving the mandrel transversely to the cordage to wind the twisted length of cordage in a compact helix against the action of the tensioning means attached to the slidable clamp, and means operable by the slidable clamp for terminating the operation of the mandrel when a predetermined amount of the length of cordage is wound thereon.

6. An apparatus for forming multi-conductor cordage having a vulcanizable jacket into retractile cords, which comprises a rotatable chuck designed to receive one end of a length of cordage required to make a retractile cord, an elongated track having its longitudinal axis substantially aligned with the rotating axis of the chuck, a clamp positioned movably in the track and held thereby against rotation, said clamp being designed to grip the opposite end of said length of cordage, means attached to the clamp for urging the clamp away from the chuck and thereby hold the length of cordage taut between the chuck and the clamp, means for rotating the chuck so as to impart a predetermined longitudinal twist to the length of cordage, a mandrel positioned adjacent to the chuck and transversely to the length of cordage, means for clamping the end of the twisted cordage previously held in the chuck to the mandrel, means for rotating the mandrel in such a direction as to wind the twisted length of cordage on the mandrel in a compact helix against the action of the urging means attached to the clamp, means for moving the mandrel transversely with respect to the cordage so that the adjacent convolutions of the helix abut each other, and means for clamping the end of the cordage previously secured in the clamp to the mandrel to hold the helix on the mandrel so that the wound cordage may be set in its helical, twisted shape.

7. An apparatus for forming multi-conductor cordage having a vulcanizable jacket into retractile cords, which comprises a rotatable chuck designed to grip one end of a length of such cordage required to make a retractile cord, an elongated track having its longitudinal axis aligned with the axis of the chuck, a carriage positioned movably in the track, a clamp mounted on the carriage to grip the opposite end of said length of cordage, means attached to the carriage for urging the carriage away from the chuck to tension the length of cordage between the chuck and the clamp, means for rotating the chuck to impart a predetermined, longitudinal twist to the length of cordage, a mandrel positioned transversely to the length of cordage, means positioned on the mandrel for clamping the end of the twisted cordage previously held in the chuck to the mandrel, means for rotating the mandrel in such a direction as to wind the twisted length of cordage on the mandrel against the action of the tensioning means in a compact helix having a pitch in the same direction as that of the twist imparted to the length of cordage, whereby the torsional stresses resulting from twisting the cordage tend to force the adjacent coils of the helix together, and means positioned on the mandrel for clamping the end of the cordage previously secured in the clamp to the mandrel to hold the helix on the mandrel in its compact form.

8. An apparatus for forming a plurality of individually insulated conductors enclosed in a vulcanized jacket into retractile cords, which comprises a rotatable chuck designed to grip an end of such cordage, a slidable clamp, tensioning means attached to the clamp for holding a length of such cordage required to make a retractile cord under tension between the chuck and the clamp, means for rotating the chuck to twist the cordage in a direction such as to produce torsional stresses in the entire length of cordage, means for terminating the twisting of the cordage when it has been twisted the number of times required for the length of cordage held between the chuck and theclamp, means for winding the twisted cordage into a compact helix against the action of the tensioning means in such a direction that the pitch of the helix is in the same direction as the pitch of the twist previously applied to the cordage, said holding means being designed to create a tension on the cordage suificient to hold the cordage taut against the action of the torsional stresses set up by twisting the cordage and to cause the cordage to form a helix of uniform diameter as it is formed on the Winding means, and means operable by the slidable clamp for terminating the operation of the winding means when a predetermined length of the twisted cordage is wound on the winding means.

9. An apparatus for forming multi-conductor cordage having a vulcanizable jacket into retractile cords, which comprises a rotatable chuck designed to grip one end of a length of such cordage required to form a retractile cord, a clamp movable longitudinally with respect to said chuck and designed to grip the opposite end of said length of cordage, tensioning means for urging the slidable clamp away from the chuck with a force sufcient to hold the said length of cordage taut between the chuck and the slidable clamp, means for rotating the chuck to impart a predetermined,

longitudinal twist to the length of cordage, means for winding the twisted length of cordage in a helix against the action of the tensioning means, in such a direction that the twist in the cordage urges the adjacent convolutions of helix together, means for moving the winding means transversely with respect to the length of cordage so that the adjacent convolutions of the helix abut each other, means operable by the movable clamp to render the winding means inoperative when a predetermined length of the cordage is wound in a helix thereon, and means for clamping the helix on the winding means so that the helix may be set in its helical, twisted form when the clamping means are removed from the mandrel.

WILLIAM L. AMES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,173,096 Campbell Sept. 19, 1939 2,248,149 Wilson July 8, 1941 2.413.715 Kemp et a1. Jan. 7, 1947 Certificate of Correction Patent No. 2,565,465 August 28, 1951 WILLIAM L. AMES It is hereby certified that error appears in the printed specification of the above numbered patent requlring correctionas follows:

Column 9, line 24, for contact 341 read Contact 241; column 12, line 11, for terminals 203 read terminals 235;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 20th day of November, A. D. 1951.

THOMAS F. MURPHY,

Assistant Oommz'ssioner of Patents. 

